Repairing Damage to HD Galvanized Pipes Before Painting

Please need experts help on this matter,

Bended Fire water pipe (3"& 4") erected around tank having damages linearly at expansion and contraction side of pipe. Our client says to replace the pipe which was damaged, its sub-contractor mistake that they didn't detect the surface discontinuities of pipe after bending or before taking in process of galvanization. Nominal thickness of pipe is under acceptable limit only matter is galvanization, if I will suggest to client to repair the damages as below,

Take out laminations by power grinder/sander and make smooth landing of end of all metal laminations and close all opening by metal putty prior to go for initial coat.

''Is it necessary to replace the pipes as client says or we have to take remedial action as I explained above? Guide me to use proper method to repair the galvanization if there is any"

Thanks,

ADEEL-TRG-KSA